Hostile umber hulks can also be useful for tunnelling purposes; simply try to avoid killing them unnecessarily.

Origin

The "Umber hulk" is an insectoid monster originating from Dungeons and Dragons. It has mandibles, exoskeleton and antennae like a beetle, but two limbs like a primate, and walks in a semi-erect manner similar to that of a gorilla. It has four eyes -- two small and two large -- with which it causes confusion.

The umber hulk should not to be confused with the better-known but unrelated large humanoid "green Hulk", or one of its spinoffs, the large humanoid "red Hulk". Umber is a natural pigment of reddish-brown color, adding to the confusion.

Encyclopedia entry

Umber hulks are powerful subterranean predators whose
iron-like claws allow them to burrow through solid stone in
search of prey. They are tremendously strong; muscles bulge
beneath their thick, scaly hides and their powerful arms and
legs all end in great claws.